1. Field of the Invention
The invention relates in general to a light emitting element, and more particularly to a semiconductor light emitting structure with a patterned structure.
2. Description of the Related Art
Light emitting diode (LED) emits the light through photoelectron conversion. The main constituting material of the light emitting diode is semiconductor, wherein the semiconductor with a higher ratio of holes carrying positive charges is referred as a P-type semiconductor, and the semiconductor with a higher ratio of electrons carrying negative charges is referred as an N-type semiconductor. A PN joint is formed at the junction between the P-type semiconductor and the N-type semiconductor. When voltages are applied to the positive electrode and the negative electrode of an LED, electrons and holes are combined and emitted in the form of the light.
Due to the advantages of long lifespan, low temperature and high energy utilization rate, LED has been widely used in backlight modules, lamps, traffic lights, and brake lights, and has gradually replaced conventional light source.
However, the refractive index of the LED semiconductor substrate is far larger than the refractive index of the air, and the light emitted from the LED semiconductor and radiated toward the substrate may easily enter the substrate, but the light entering the substrate will be returned due to the total reflection at the substrate/air interface. As most of the light is confined in the substrate, the light cannot be emitted out, and the light extraction efficiency is not satisfactory.